On Fri, Nov 14, 2014 at 05:24:33PM +0000, Damien Lespiau wrote:
> On SKL DPLL0 is used to derive CDCLK but can also be used to drive an
> eDP port (as long as we don't want SSC). DPLL0 is special enough to not
> be handled by the shared DPLL framework (drives CDCLK, not supposed to
> enable the HDMI mode), So we need to compute the configuration
> separately from the other DPLLs.
>
> Note that we don't need to reprogram DPLL0 (which would mean bringing
> down CDCLK) to support the various eDP 1.3 link rates as they all share
> the same VCO (8100).
>
> Signed-off-by: Damien Lespiau <damien.lespiau@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/intel_ddi.c | 20 ++++++++++++++++++++
> drivers/gpu/drm/i915/intel_dp.c | 31 ++++++++++++++++++++++++++++++-
> 2 files changed, 50 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index ca33ee9..596bdc1 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -1484,6 +1484,25 @@ static void intel_ddi_pre_enable(struct intel_encoder *intel_encoder)
> uint32_t dpll = crtc->config.ddi_pll_sel;
> uint32_t val;
>
> + /*
> + * DPLL0 is used for eDP and is the only "private" DPLL (as
> + * opposed to shared) on SKL
> + */
> + if (type == INTEL_OUTPUT_EDP) {
Are you sure you really want to check for edp here and not for something
more specific like port A? Same with the is_edp check below.
In the past we've had piles of fun with code that checked for is_edp, but
which should have checked for port A or something similar - on desktop
platforms (at least in all chips thus far, dunno about skl) edp ends up on
port D.
Oh and someone bored might want to replace the pile of type == DP || type
== EDP checks in intel_ddi.c with config->has_dp_encoder.
I'll hold off on merging this for now just out of curiosity ;-)
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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